The present invention relates generally to low pressure hydraulic pumps and more particularly to a hydraulically driven, pressure compensated, self-priming, low-pressure hydraulic pump.
In the past, complex and expensive pumps were required to obtain pressure compensated, self-priming, low pressure operation and attempts to make direct pressure-operated reciprocating piston pumps were frustrated by the incompressibility of hydraulic fluid which would present totally bi-stable operation of the free piston.